Concreting operations are the most important and critical steps in the reinforced concrete construction cycle. Issues about how to assure safety of the workers and the structure during the concreting operations have long been the topic of significant research efforts. A study by Hadipriono and Wang [1] on the falsework collapse during the construction stage, shows that nearly half of the collapses took place during concrete pouring. Though the causes of the collapse are varied and sometimes unclear, most of these causes could have been eliminated through safety inspection in advance.

Conventionally, concreting safety inspection is conducted before or during the concreting operations with a preprinted, general purpose checklist that covers the most significant items of the target operations. Physical observation comments on each inspection items are made and recorded on the checklist by the inspector. This kind of paper-based inspection checklist has been accepted industry-wide as a means of improving construction safety and quality.

However, there are some drawbacks to the conventional paper-based inspection checklist. First, the checklist often contains vaguely worded questions. Usually inspection checklists are designed to fit a variety of construction projects regardless of the unique attributes of each project. As a result, the descriptions of inspection items on a paper-based checklist tend to be vague and ambiguous. Consequently, the inspectors find it difficult to make specific comments when addressing vaguely worded questions. For instance, "Check all bracing and shoring to ensure that it has not been loosened or misplaced." To make an inspection comment on this item, the inspector has to determine the definition of loosened and misplaced. How loose is loosened and what is the so-called misplaced distance? As another example, it is also very difficult for the inspector to make the expected precise and "crisp" comments on vague inspection descriptions, because in reality, the inspection items are neither distinctly positive nor negative but lie somewhere between yes/no, or pass/not-pass.

Aside from the vagueness, another drawback in the conventional inspection checklist stems from completed checklist tending to be non-informative since inspection comments are formulated as either yes/no or pass/not-pass without further explanation. For most cases, these kind of yes/no and pass/not-pass comments give very limited information about the real construction situation. Furthermore, the result comments seem to be independent each other and given equal importance. Actually, inspection items should be interrelated with each other and ranked in accordance with their significance.

The time frame of this evaluation will begin at the time when all the formwork, reinforcement and other preparatory activities are finished and end at the time when the concrete pouring is complete. As to the scope of this software, it is limited to the concreting operation. Items related to hidden procedural problems and most structure internal problems are assumed to be sound and are not involved in this software. Hidden procedural issues, for example, management-related issues, communication-related issued, contractual-related problems, are outside the scope of this program. Most structural internal issues, for example, design-related, detailing-related, construction- related, and material-related problems also are outside the scope of this program. However some critical design and construction related problems specific to the concreting process that could enable failure are included as a part of the inspection list in the program.

This paper introduces a methodology that uses fuzzy logic to evaluate concreting operations. Fuzzy logic is an ideal tool for treating vagueness and ambiguity contained the linguistic descriptions in the inspection items and inspection comments. The evaluation software accompanying this paper which utilizes the fuzzy logic overcomes the vagueness and ambiguity in the conventional paper-based inspection. Performance and the final evaluation of the concreting operations are two main outcomes that this software provides. First, performance on concreting operations is shown graphically in two ways; the performance from the comments made by inspector and the performance from the view of inspection significance. Second, the final evaluation result is given as a rated value with graphs that are more informative and readable than the conventional inspection results on a paper-based checklist.

1

F.C. Hadipriono, H.K. Wang, "Analysis of Causes of Falsework Failure in Concrete Structures", Journal of Construction and Management, ASCE Vol. 112, No. 1, 1986. doi:10.1061/(ASCE)0733-9364(1986)112:1(112)

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